Laser bonded tamper proof press-on cap and seal

Abstract

There is disclosed a press-on cap having a flat top with a cylindrical skirt with an annular tear band defined by a pair of annular score lines, and with at least two annular inner beads which seat in annular grooves in the neck of a bottle. The cap skirt extends below the lower score line of the annular tear band to form a tamper-proof ring which is bonded by laser radiation at least one, preferably two, spots to the neck of the plastic bottle. The spot bonds preferably have a diameter no greater than about 0.15 inch. The invention also comprises a bottle filler line which includes a capping station in which caps are applied and pressed downwardly over the narrow necks of the bottles which have been filled with a liquid such as milk or non-carbonated beverage, and a cap bonding station in which the capped and filled bottles are passed between laser beam effectors which are pulsed momentarily to spot bond the tamper-proof rings of the caps to the necks of the bottles.

What is claimed is: 
     
       1. In a bottling line having a filling station for filling plastic bottles with comestible liquids, each of the bottles having an open neck at its upper end with a neck finish including a plurality of grooves extending circumferentially about the neck, said bottling line including a capping station for capping the filled bottles with press-on plastic caps, each cap having a top disc and a downwardly dependent skirt with sealing beads on the inner wall of said skirt to seat into said bottle neck finish grooves, said bottling line including a bottle conveyor for transporting empty plastic bottles to said bottle filling station, with the bottle filling station having an automated bottle filler with a plurality of filler valves with means to move the valves into registration with the open necks of respective bottles delivered by the conveyor and including filler controls for metering a measured quantity of said comestible liquid into the bottle and including a filled bottle conveyor to received filled bottles from said filler station and transport the filled bottles in single file to said capping station, with the capping station including a cap conveyor to deliver, place and secure a single cap on each of the filled bottles during their transport on said filled bottle conveyor, the improvement comprising: a. said press-on plastic bottle caps each having an annular tear band defined by a pair of spaced apart circumferential grooves about said skirt to permit the user to separate the cap into a top reclosure cap and a bottom tamper proof ring, and at least two sealing beads extending circumferentially about the internal wall of said skirt, at least one of which is located above said tear band;   b. a cap to bottle bonding station incorporated into said bottling line following said capping station and including: 1. at least two laser beam end effectors comprising an internally reflecting light tube terminating in a laser beam focusing element which are spaced at opposite sides of said filled bottle conveyor and are positioned to discharge a focused laser beam on said tamper proof ring of each of said plastic caps when the respective filled and capped bottle is at a target location between said effectors, during the transport of the filled and capped bottles on said filled bottle conveyor; and   2. a laser beam generator and controller including a power supply, controller and multiplexer with multiple fiber optic beam delivery cables extending from said generator and controller to each of said laser beam end effectors to apply at least two laser-welded spots at a circumferentially spaced-apart angular increment about said tamper proof ring to bond said ring to said neck of said plastic bottle.     
     
     
       2. The improvement in said bottling line of claim 1 which also includes a filled and capped bottle sensor to detect the position of filled and capped bottles relative to said laser beam during their transport on said filled bottle conveyor and control means responsive thereto to direct laser beam energy from said end effectors when a filled and capped bottle is positioned at the target location between said effectors. 
     
     
       3. The improvement in said bottling line of claim 1 wherein said laser beam end effectors are positioned at a 180-degree angular increment. 
     
     
       4. The improvement in said bottling line of claim 1 wherein said laser beam end effectors are focused and positioned to apply laser welded spots having generally cylindrical areas with diameters no greater than about 0.15 inch. 
     
     
       5. The improvement in said bottling line of claim 1 wherein said press-on cap also includes at least one sealing beam about the inner wall of its skirt extending circumferentially about said tamper proof ring.